Cooling system



June 18, 1940- J. M. THO'MPSON CDOLING I SYSTEM Filed Dec. 27, 1957 2Sheets-Sheet 1 w N a .9 W m T /M/%/ m June 18, 1940. J M THOMPSON2,205,128

COOLING SYSTEM Filed Dec. 27, 1937 2 Sheets-Sheet 2 JaakZ 720/3050 5 47-TO/P/VEV Patented June 18, 1940 UNITED STATES? PATENT OFFICE 3 Claims.

This invention relates to cooling systems and, as illustrated herein,relates more particularly to air cooling and cleansing systems for usein motor vehicles, such as automobiles, airplanes, motorcycles or thelike.

An object of the presentinvention is to provide an improved air coolingsystem. object of the invention is to provide such a cooling systemhaving improved means for delivering and circulating air and cleansingthe same. Still another object is to provide an effective system for aircooling generators while at the same time preventing dirt, dust or otherforeign substances, which have an injurious abrasive effect upon the rrotating parts and bearing surfaces, from cir ulating within thegenerator. Still another object of my invention is to provide animproved cooling cap for generators which can. be inexpensivelymanufactured and which can be used to replace non-cooling generator capsnow in use. A further object of my invention. is to provide such a capfor generators which will effectively prevent abrasive substances frombeing circulated in the cap and from which the heated air will beeffectively withdrawn after it has performedits cooling operation. Stillanother object of the pres-- ent invention is to provide improvedstationary cooling means for a generator for motor vehicles so locatedthat when. the generator is exposed to the action of the air currentinduced by movement of the vehicle, or by the action. of a fan, the airis caused to circulate within these cooling means and the generatorcasing to cool the generator parts therein, improved means alsopreferably being provided whereby dust and other foreign substances areprevented from passing tosaid generator parts. These and other objectsof my invention will be apparent from'the following description.

In the accompanying drawings I have shown, for purposes of illustration,one embodiment which my invention may assume in practice.

In these drawings:

Figure l is a view in side elevation of a vehicle provided with oneembodiment of the present invention:

Figure 2 is an enlarged side elevation of the generator shown in Figure1; I

Figure 3 is a view in front elevation of the structure shown in Figure2;

Figure 4 is a view in rear elevation thereof;

Figure 5 is a view in section on a further enlarged scale, taken alongthe line 5-5 of Figure 3;

Another Figure 6 is a View, partly in section, taken along the line 6-6of Figure 5;

Figure 7 is a perspective view, illustrating the end cap having portionscut away to receive the ventilating members, and

Figure 8 is a perspective View of the ventilating members.

The present invention, as shown in Figure 1, is illustrated as appliedto a motorcycle, and it will be noted that agenerator 2 is mounted onthe upper forward portion of a crankcase 4 of an engine 6, thisgenerator being equipped with my improved cooling means as hereinafterdescribed.

One end of the armature shaft 8, journalled in suitable bearings in thegenerator casing or housing 9, is connected to the crank shaft of theengine 6 in any suitable manner, for example; by gears or by a chain andsprocket so that an armature ID mounted thereon may be rotated toproduce electrical energy when the engine 6 is operated. The other endof the armature shaft 8 is provided witha commutator l2 which is engagedbybrushes mounted in holders l4 and I6, for collecting and transmittingthe electrical energy produced, through suitable connections to astorage'battery or other electrically controlled or operated devices. 1

As shown most clearly in Figure 6, the generator casing 9 is open at oneend to receive the brush holders l4 and I6 and to permit access thereto.It is-usual to provide a cap or cover l8 for this open end. Further dueto the exposed location of the generator, it has heretofore been thepractice to use a totally closed cap and thereby exclude circulating airfrom the interior of the generator because of the fact that the airflowing around the generator contains a relatively large amount of dirt,sand, dust and other foreign matter which would have an injuriousabrasive effect on the moving parts, causing rapid wear of the same.

This has resulted in other difficulties. Thus, while when a motorcycleor other motor vehicle is stationary, the engine ordinarily is idlingand the load on the generator is relatively light, when the vehicle isin motion and, as its speed increases up to approximately twenty-fivemiles per hour, the charging rate of the generator increases and thebrushes of the generator are adjusted to a point where the generator isoften heavily overloaded. Motorcycle generators are designed to operateunder a load of approximately ten amperes and this ordinarily issuflicient to keep the storage battery on the vehicle fully charged, butit has become a rather usual practice to provide supof a current of air.

plementary lights, horns and electrically operated or controlled devicesso that a charging rate of ten amperes is not sufficient to keep thestorage battery fully charged. To keep the battery fully charged, thecharging rate of the generator is increased to eighteen or twentyamperes. This, of course, causes the generator to heat excessivelyunless some means is used to cool the generator. In fact, thetemperature of a generator equipped with the usual closed cap, oftenreaches F. or more, with the result that the armature burns out after arelatively short period of use.

To avoid this difiiculty, I provide improved cooling means adapted totake advantage of the fact that the generator 2 is mounted on themotorcycle forwardly of the engine 6 so that the end of the generatorcarrying the cover I8 is exposed to the action of a stream of cool airwhen the motorcycle is in motion. Further, although the generator 2 isstationary relatively to the motorcycle and the engine 6 on which it ismounted, I have provided improved means for utilizing this cool airstream so that the parts of the generator 2 will be effectively cooledwhen the generator is operating under a heavy load.

The present invention provides improved means for permitting air toenter the cover I8 and circulate therein, and thus cool the heated partswhile at the same time trapping and discharging foreign matter containedin the air to prevent such foreign matter from injuring the moving partsand bearing surfaces of the generator. The cover, i8, is provided with aconvex end portion I9. This end portion is suitably recessed, herein atdiametrically opposed points 2I and 23, to provide seats for the cap !8when it is placed in operative position over the end of the casing 9 ofthe generator, and each recessed portion 2| and 23 has a hole therein toreceive a suitable screw I811 for securing the cap or cover I8 inoperative position on the generator. The lower portion or side of thecover I8 is cut away as shown at Zn in Figure '7 to form an openingadapted to receive a curved plate 22 which is brazed, welded or otherwie suitably secured to the cover I8. The curved plate 22 is formed with aplurality of hoods or openings 24 on the bottom of the plate, which areso arranged that they are directed forwardly into the path of movementThe openings 24 are formed in the plate 22 by cutting three slits in theplate and then raising the portions 25 of the plate behind these slits.It is to be noted that the openings 24 are offset with respect to eachother to insure that each opening will he unobstructed to permit themaximum amount of air to enter the same. These openings 24 are coveredby screens 25 which remove the larger particles of dust, sand or otherforeign matter from the air which is to enter the cover !8 but which. donot remove all harmful abrasive foreign matter which would produceexcessive wear on the bearings and moving parts of the generator ifallowed to come into contact therewith. Some of the remaining foreignmaterial adheres to the inside portion of the plate 22 and to remove theremaining foreign matter, a deflecting member or plate 28 is provided inthe rear portion of the plate 22. This extends inwardly and downwardlyat an angle of approximately 45 to the tangent to cause other particlesof dirt or other foreign matter to be deflected downwardly and outwardlythrough a narrow slot 30 formed in the plate 22. Due to the relativelyhigh speed at which the air is forced through the openings 24, the

relatively heavy particles of dust, sand and other foreign matter, tendto move in a straight line along the inside surface of the plate 22 andbetween the latter and the adjacent portions 22a of the cover I8 in suchmanner as to be kept out of the generator brushes and delivered throughthe opening 20 substantially within the vertical limits of the deflector28. Consequently, the greater portion of these particles is trapped bythe deflecting or bafiie plate 28 and discharged through the narrow slot30. The remaining cleaned portion of the air which has entered theopenings 24 is free to circulate within the casing I! and the cover I8to cool the heated parts.

The cover I 8 is also provided opposite the opening 20, with a V-shapedopening 32 which is adapted to receive a plate 34, welded, brazed orotherwise suitably secured to the cover I8 over the opening 32. Theplate 34 is curved transversely at its rear end so that a rearwardlydirected opening 35 is formed between the plate 34 and the cover IS. Theopening 3'5 may, as illustrated, be covered by a screen 38. After theair has circulated within the casing. as above or al described. itpasses through the V-shaped opening 32 and then through the opening 36.The circulation of the air is facilitated by the fact that when a motorvehicle is traveling at a relatively high rate of speed, a partialvacuum is created behind the opening 35. This partial vacy uum causesthe air contained in the casing to move therethrough much faster thanwould otherwise normally occur. It is to be noted that the parts abovereferred to are static ar; relatively to each other, to the genera or onwhich :1,

they are mounted, and to the engine 5 on which the generator is mounted.Considerable air pressure is set up when the motorcycle is in motionwhich will cause the air received by the apertures 24 to be circulatedwithin the generator casing and the exhaust aperture 36 will cooperatetherewith to circulate and to deliver the air from the casing 9.

It is to be noted that the comb ned area of the apertures or openings 24is slightly less than the area of the exhaust aperture 36. If thecombined area of the openings 24 is too great, undesirable currents ofair will be set up inside of the generator which would prevent effectivetrapping and discharging of foreign matter by the deflecting or baffleplate 28. On the other hand, if the exhaust aperture 36 is too large ascompared to the openings 24. the air will be circulated through theinterior of the generator at such a high rate of speed that effectivetrapping and discharging of foreign matter through the slot 30 would nottake place. The slot 30 must also be of a predetermined size to insurethat foreign matter will be effectively discharged. It has been foundthat the combined area of the slot 30 and the openings 24 should besubstantially equal to the area of the exhaust opening 36 and that thearea of the slot 30 should be approximately onc-third of the combined ofthe openings 24 to produce the most satisfactory results. It is to beunderstood, however, that these proportions may be varied depending uponthe conditions under which the generator is used.

In the illustrated embodiment of the invention, the air is caused tocirculate only about the commutator and the adjacent end of thearmature. This has been found sufficient to reduce the temperature ofthe armature approximately 30 per cent. It is evident, however, that theair could circulate aboutthe whole armature if desired. A portion of thearmature, about which the air does not circulate to any marked degree,is cooled by conduction. The field windings of the generator are cooledto great extent by the movement of air about the outside of the casing9.

After the cap or cover It has been assembled, it is placed on thegenerator 2 and secured in position with the apertures 24 directed intothe path of movement of the current of air. As illustrated, thegenerator 2 is disposed with its axis substantially at right angles tothe path of movement of the motorcycle but it is apparent that, in othervehicles, the axis of the generator could be disposed at other angles tothe path of movement, depending upon the direction of the movement ofthe air to the generator. It is desirable that the openings 24 should bepositioned at sub stantially right angles to the path of movement of thecurrent of air, to produce the best results.

It is apparent that, with the above arrangement, the air which entersthe generator casing is free from dust or foreign matter and that thisis accomplished while obtaining a flow of air of large volume into thegenerator casing and through the latter. Furthermore, the cap I8 isinexpensive to manufacture and, consequently, does not materiallyincrease the cost of the generator. By the use of the cap or cover I8,above described, the operating temperature can be decreased by as muchas 30 per cent which will aid materially in increasing the life of thegenerator and in reducing the expense of operating the vehicle.

Although the invention has been described and illustrated as applied toa motorcycle, it is evident that it could also be used in other motorvehicles or applied to generators operated by stationary engines wherethe air is caused to flow past the generator by the use of a fan orother suitable means. Moreover, it will be evident that my improvedstructure may also be applied to use on motors of various types, and onother parts which it is desired to air cool, or air cool while cleansingthe air, such as other parts of an automobile, motorcycle, or airplane,which tend to heat in operation while air flow is available to cool thesame. For example, where the landing fields are dusty, the conditionssurrounding the use of airplane equipment are closely similar to thosein a motorcycle. Also, while my improved cap has been described andshown as formed of a plurality of parts, it is evident that the cap Icould be formed in one part if it were found desirable or economical todo so.

While I have in this application specifically described only oneembodiment of my invention, it will be understood that this embodimentis shown for purposes of illustration, and that the invention may bemodified without departing from its spirit or the scope of the appendedclaims.

What I claim as new and desire to secure by Letters Patent is:

1. In a cooling cap for generators having a generally cylindricalgenerator casing arranged in an external air stream set up by bodilymovement of the generator, a generally cylindrical cap adapted toenclose one end of said casing and spaced from said casing to form anannular chamber therewith, passage forming means on said cap disposedtangentially thereof close to the outer periphery thereof and openingtransversely to the generator axis and directing air from said airstream tangentially into said cap along the inner wall thereof,tangentially disposed exhaust passage forming means on said cap close tothe outer periphery thereof and oppositely directed relative to saidinlet passage forming means and opening transversely to the generatoraxis on the opposite side of said cap from said inlet passage formingmeans for sucking air tangentially from adjacent the inner wall of saidcap and cooperating with said inlet passage forming means to set up anair flow through said cap between said inlet and exhaust passage formingmeans, means for separating the larger foreign particles from the airentering said cap, and means within said chamber for separating smallerforeign particles from the entering air stream and discharging the sameinto the outside air stream.

2. A generator cooling system arranged in an external air stream set upby bodily movement of the generator comprising in combination, agenerally cylindrical generator casing, a cylindrical cap enclosing oneend thereof and spaced from said casing to form an annular chambertherewith, passage forming means on said cap disposed tangentiallythereof close to the outer periphery thereof and opening transversely tothe generator axis and directing air from said air stream tangentiallyinto said cap along the inner wall thereof, tangentially disposedexhaust passage forming means on said cap close to the outer peripherythereof and oppositely directed relative to said inlet passage formingmeans and opening transversely to the generator axis on the oppositeside of said cap from said inlet passage forming means for sucking airtangentially from adjacent the inner wall of said cap and cooperatingwith said inlet passage forming means to set up an air flow through saidcap between said inlet and exhaust passage forming means, means forseparating the larger foreign particles from the entering air, and meanswithin said chamber for separating smaller foreign particles from theentering air stream and discharging the same into the outside airstream.

3. A generator cooling system adapted to be responsive to an externalair stream flowing in a radial direction to the generator comprising incombination, an electrical generator of cylindrical form having a capenclosing one end thereof, inlet passage forming means on said capdisposed tangentially thereof close to the outer periphery thereof andopening transversely to the generator axis and directing air from saidair stream tangentially into said cap along the inner wall thereof, andtangentially disposed exhaust passage forming means on said cap close tothe outer periphery thereof and oppositely directed relative to saidinlet passage forming means and opening transversely to the generatoraxis on the opposite side of said cap from said inlet passage formingmeans for sucking air tangentially from adjacent the inner wall of saidcap and cooperating with said inlet passage forming means to set up anair flow through said cap between said inlet and exhaust passage formingmeans, said cap having an air inlet aperture enclosed by said tangentialinlet passage forming means, and means including a member projectingtransversely of the air stream flowing into said aperture for separatingand discharging from said cap foreign particles in said entering airstream. JACK M. THOMPSON.

